The justice secretary and I don’t seem to agree on much at the moment. But one thing we do have in common: last year, Michael Gove wrote, “Do I think Of Mice And Men, Lord Of The Flies and To Kill A Mockingbird are bad books? Of course not. I read and loved them all.”

Admittedly, he was responding to reports that he wanted to ban Harper Lee from the GCSE syllabus, in favour of English writers – a claim he denied. But since Gove might preside over our justice system for the next half-decade, I am delighted he loved To Kill A Mockingbird; in fact, I would suggest he take a break from drawing up plans to repeal the Human Rights Act and reread it. Perhaps it will make him think twice.

The novel had a profound effect on me. When I first read Mockingbird, as a teenager in 1980s north-west London, I was utterly transported – to small-town 1930s Alabama, a place of spittoons, shingles, scolds and smilax. To Maycomb, with its chinaberry trees, rabbit-tobacco and single taxi – where there was “no hurry, for there was nowhere to go”. To the world of the wonderfully funny and audacious Scout – a timeless heroine for every little girl with a head full of questions and an appetite for a good fight (“He said I was the only girl he would ever love, then he neglected me. I beat him up, but it did no good”). It seemed so real to me; I could taste the scuppernongs and smell the sweet talcum.

I wasn’t the first led into law by Atticus Finch, and I won’t be the last. I realise it is less admired by scholars than by fans (“sugar water served with humour”, wrote one critic). But it is this simplicity and lack of pretension that helps it pack its considerable punch. It is accessible, touchingly human and intimate; it also tackles enduring questions of discrimination and injustice.

The lessons Scout learned stayed with me. Working for Liberty, I have often thought back to Atticus’s advice to his daughter: “No matter what anybody says to you, don’t you let ’em get your goat. Try fighting with your head for a change.” And I have thought of his definition of courage: not “a man with a gun in his hand”, but “when you know you’re licked before you begin, but you begin anyway and see it through no matter what”. Atticus gave Scout values to commit to and live by, and generations of young readers, consciously or subconsciously, have committed to them, too. None of us will ever be as unimpeachable as Atticus, but it can only be a good thing to try. “You never really understand a person until you consider things from his point of view… until you climb into his skin and walk around in it,” Atticus tells his children; even after the trial, he can put himself in Bob Ewell’s shoes.

I still recall the shiver down my spine when I got to the end of that heartbreaking courtroom scene. I cried with Dill, and felt Jem’s indignation when he shouted, “It ain’t right, Atticus!” But real change takes baby steps, battle after battle, until the fight is won. Mockingbird was published 12 years after the Universal Declaration of Human Rights, six years after Brown v Board of Education (marking the end of segregation in schools), and five after the Montgomery bus boycott which began with the arrest of Rosa Parks. Yes, Tom Robinson is found guilty – but the jury stays out for hours, not minutes. The message is hope; for real progress towards a society based on individual human dignity, equal treatment and fairness.

We all believe in human rights: our own, or those of people we love. It’s when they apply to others that problems arise

Gregory Peck in a courtroom scene from To Kill A Mockingbird. Photograph: Rex

We’re not there yet; Ferguson, Baltimore, Staten Island show all too brutally that the fight for equality goes on. As President Obama said last month, we are not cured of racism: “Societies don’t overnight completely erase everything that happened 200 to 300 years prior.” And while modern Britain is mercifully far removed from the segregated south of the 1930s, we have been assailed by similarly dehumanising rhetoric in recent years, in our politics and in the press – a language of fear that seeks to cement a baseless dread of “otherness”. This is not just the scapegoating of migrant groups, but the redirection of anger towards our poorest neighbours: “hard-working families” and “strivers” pitted against “shirkers” and “scroungers”. “There’s something in our world that makes men lose their heads,” Atticus says. That something is still there. We are all capable of individual empathy, but our collective empathy sometimes fails. As grownups, we no longer “cry about the simple hell people give other people – without even thinking”, just as Dolphus says Dill will eventually cease to do.

We all believe in human rights: our own, or those of the people we love, or of “people like us”. It’s when they apply to “others” that problems arise. The principle of equal treatment under the law provides the solution. Legal language calls it nondiscrimination; we know it as empathy. Walking in another person’s shoes doesn’t require a blind disregard for the greater good. But it does demand a modicum of respect for others – even those who have lost respect for themselves. It can’t be rationed according to nationality, skin colour, religion or wealth.

What might Atticus, Scout or Tom say if they could see us now, lucky enough to live in a country where fundamental rights – to a fair trial, to not be tortured or enslaved – are enshrined into law, while others still struggle for them? What would they say if they knew our government wanted to dismantle that law in favour of a “British Bill” that would let politicians end the universality of rights protections, and pick and choose which – and whose – matter most?

With luck, Go Set A Watchman will introduce a whole new generation to To Kill A Mockingbird – and I hope adults will reread it, too. A great story, well told, has the power to move more than speeches, journalism and polemic. Harper Lee’s messages of respect for human dignity, equality and, above all, hope are as urgent now as they were in 1960.